I saw a iptable command like this:
iptables -t nat -A xx -p tcp -m tcp --dport 80 -j DNAT --to %myweb%:80
what's "%" there for? Thanks. Where I can get a manual to tell me what kind of symbols I can use?
Well, the iptables
command there sets up a port forward on TCP from external port 80 to internal port 80 forwarded to whatever IP address or domain is represented by %myweb%. %myweb% seems to be in the same format that Windows uses for its environment variables (on *nix system it would be $MYWEB).
Where did you get this iptables command from? It could just be that the command is an example, and they mean you to manually reply %myweb% with the IP address of your internal web server. Alternately, if it's part of an iptables script, then %myweb% could be getting replaced with the contents of a variable. It's hard to say for sure without knowing its source.